Industrial chemicals · Taylor, TXTechnical Data Sheet
Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye)
Membrane Grade · 50%
- CAS number
- 1310-73-2
- UN number
- UN1824
- Hazard class · packing group
- 8 · PG II
- Structure
Structure · PubChem - Grade
- Membrane Grade · 50%
- Signal word
- Danger
- Hazards
- Proper shipping name
- Sodium hydroxide solution
Identity & Composition
- Product Name
- Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye)
- Alliance Code
- sodium-hydroxide-50-membrane-grade-caustic-soda-lye
- Grade
- Membrane Grade
- Concentration
- 50%
- CAS Number
- 1310-73-2PubChem
- Formula
- NaOHAdjudicated
- Molecular Weight
- 39.997PubChem
- Product Type
- Solution
Specifications
| Test | Specification | Typical | Method | Source |
|---|---|---|---|---|
| Assay, sodium hydroxide (NaOH) | 49.5 – 51.5 WT. % | 50.3 WT. % | Titrimetry | Interpreted |
| Sodium Chloride (NaCl) | 100 PPM max. | 23 PPM | Turbidimetry | Interpreted |
| Iron (Fe) | 3 PPM max. | 0.57 PPM | Colorimetry | Interpreted |
| Sodium Carbonate (Na2CO3) | 0.1 WT. % max. | 0.045 WT. % | Titrimetry | Interpreted |
| Sodium chlorate (NaClO3) | 40 PPM | 40 PPM | Ion Chromatography | Interpreted |
| Sodium sulfate (Na2SO4) | 40 PPM | 8.8 PPM | Ion Chromatography | Interpreted |
| Nickel (Ni) | 1.0 PPM Max | 0.21 PPM | ICP-OES | Interpreted |
| Mercury (Hg) | 0.05 PPM Max | 0.0013 PPM | Cold vapor AAS | Interpreted |
| Color (APHA) | Max 20 | 10 | ASTM D1209 (Pt-Co) | Interpreted |
Values are reproduced from the current product reference. Source labels do not by themselves establish a supplier guarantee or a test result for your lot. Confirm applicable acceptance limits and request lot-specific documentation.
Available GradesSame CAS, alternate grades and concentrations
| Grade | Concentration | Typical Assay | SKU | TDS |
|---|---|---|---|---|
| This grade Membrane Grade | 50% | — | current | current |
| ACS Grade | 50% | — | sodium-hydroxide-50-solution-acs-grade | View TDS → |
| ACS | 30% | — | sodium-hydroxide-30-acs-grade | View TDS → |
| Technical | 30% | — | sodium-hydroxide-30-technical-grade | View TDS → |
| — | 25% | — | sodium-hydroxide-25 | View TDS → |
| ACS Grade | 25% | — | sodium-hydroxide-25-acs-grade | View TDS → |
| ACS | 20% | — | sodium-hydroxide-20-acs-grade | View TDS → |
| Technical | 20% | — | sodium-hydroxide-20-technical-grade | View TDS → |
| ACS | 15% | — | sodium-hydroxide-15-acs-grade | View TDS → |
| Technical | 15% | — | sodium-hydroxide-15-technical-grade | View TDS → |
| ACS | 10% | — | sodium-hydroxide-10-acs-grade | View TDS → |
| Technical | 10% | — | sodium-hydroxide-10-technical-grade | View TDS → |
| ACS | 5% | — | sodium-hydroxide-5-acs-grade | View TDS → |
Typical assay shown is the rolling-window mean from the sibling product's most recent lots. Grade selection drives downstream end-use — verify the sibling grade matches your specification before substitution.
Physical & Chemical Properties
| Property | Value | Source |
|---|---|---|
| Appearance | Clear, caustic liquid | Adjudicated |
| Form | Liquid solution | Published reference |
| Odor | Odorless | Adjudicated |
| pH | 13–14 | Adjudicated |
| Specific Gravity | 1.520 - 1.540 | Interpreted |
| Density | 1.53 (50% w/w aqueous solution, 20 °C) | Published reference |
| Boiling Point | 140–145 °C (284–293 °F) | Adjudicated |
| Melting Point | About 10–12 °C (50–54 °F), crystallization point | Adjudicated |
| Flash Point | Not applicable | Adjudicated |
| Vapor Pressure | 1.2 hPa (0.9 mmHg); 6.3 mmHg at 40 °C | Adjudicated |
| Solubility (water) | Completely miscible with water (strongly exothermic) | Adjudicated |
Strong base — hygroscopic; values may drift in opened containers. See storage guidance.
Materials of Construction
| Material | Rating | Conditions | Source |
|---|---|---|---|
| HDPE / polyethylene (bottle, drum) | Compatible | 50-52% (w/w) sodium hydroxide solution as packaged for sale by the supplier; no temperature stated | media.vwr.com |
Compatibility is drawn from published manufacturer and supplier documentation for this product; each rating is sourced. Confirm against your specific duty cycle before equipment selection.
Regulatory & Transport
DOT / 49 CFR
- UN Number
- UN1824Adjudicated
- Hazard Class
- 8Adjudicated
- Packing Group
- IIAdjudicated
- Proper Shipping Name
- Sodium hydroxide solutionAdjudicated
GHS / OSHA HCS 2024
- Signal Word
- DangerAdjudicated
- H-Codes (Hazard Statements)
- H290, H314Adjudicated
- P-Codes (Precautionary Statements)
- P234, P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P390, P405, P406, P501Adjudicated
Occupational Exposure Limits
- OSHA PEL (29 CFR 1910.1000)
- 2 mg/m³ TWAOSHA 29 CFR 1910.1000
- ACGIH TLV
- 2 mg/m³ CeilingAdjudicated
- NIOSH REL
- 2 mg/m³ ceilingNIOSH Pocket Guide
- NIOSH IDLH
- 10 mg/m³NIOSH Pocket Guide
Transport descriptions reflect 49 CFR 172.101 lookup at time of publication. Sourced data: NIOSH Pocket Guide for REL/IDLH, OSHA Z-Tables for PEL. Always verify against the latest regulatory text before shipment-critical decisions.
Health & Fire Hazard
Acute Toxicology
- LD₅₀ Dermal (rabbit)
- 1350 mg/kgAdjudicated
Acute toxicology values from SDS Section 11 or NIOSH RTECS.
Supplier Qualification Packet
One zipped download containing the TDS, SDS, latest lot COA (when available), and a fresh Letter of Continuing Guaranty for Sodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye). Every file included is SHA-256 hashed and listed in a manifest your QA team can audit.
Catalog EquivalentsCross-reference vs major chemical suppliers
Sigma-Aldrich
| SKU | Grade | Conc. | Match | Notes |
|---|---|---|---|---|
| S5881 | ACS Reagent | ≥97% | Unverified candidate | Reagent grade, anhydrous pellets |
Cross-references are informational. Confirm against the manufacturer's current specification before substitution. Competitor trademarks are property of their respective owners.
Applications
- pH adjustment in water treatment; pulp and paper; textile scouring and dyeing; soap and detergent manufacturing; petroleum refining and oil drilling; aluminum processing; chemical synthesisbasekim.com
Applications are drawn from published manufacturer and supplier documentation; each is sourced. Suitability for a specific use is the buyer's to confirm.
Storage & Handling
- Recommended Storage
- Store above 15 °C (59 °F): 50% caustic crystallizes at about 12 °C (54 °F). Use steel, polyethylene or polypropylene containers, never aluminum, zinc, tin or galvanized metal. Keep away from acids.Adjudicated
- Handling Precautions
- Use full PPE including chemical splash goggles and alkali-resistant gloves. Add base to water slowly with stirring. Highly exothermic dilution.Class-level guidance — not product-specific; the SDS controls.
- Incompatibilities
- Acids (violent reaction); aluminum, zinc, tin, magnesium and their alloys, including galvanized metal (releases flammable hydrogen); organic halogen compounds; nitro compounds; flammable liquids; strong oxidizers.Adjudicated
- Shelf Life
- 36 monthsmedia.vwr.comSource states a 3 year shelf-life for a 50% (w/w) sodium hydroxide solution (BDH reagent grade catalog listing); no storage conditions are stated and the source does not name membrane grade.
For full hazard, PPE, and emergency response guidance, refer to the Safety Data Sheet (SDS) for this product. The SDS controls in all cases where guidance differs.
Packaging & Logistics
Shipping Description (US DOT)
UN1824, Sodium hydroxide solution, 8, PG II
Sourced from 49 CFR 172.101. Confirm against shipping documents and carrier requirements before tender.
Revision History
Last reviewed 2026-07-06 by Andre Taki, Chief Commercial Officer, DOT Hazmat–certified (49 CFR 172.704).
| Version | Date | Change | Trigger |
|---|---|---|---|
| 1.5 | 2026-10-07 | Canonical data updated: 3 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.4 | 2026-10-05 | Canonical data updated: 18 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.3 | 2026-09-30 | Canonical data updated: 1 field changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.2 | 2026-07-22 | Canonical data updated: 2 fields changed via the provenance/adjudication pipeline.
| canonical_change |
| 1.1 | 2026-07-06 | Canonical data re-verified: 4 fields updated against independent vendor SDSs, CLP Annex VI, 49 CFR, and OSHA HazCom 2024 (GHS classification, hazard/precautionary codes, signal word, physical properties as applicable).
| canonical_change |
| 1.0 | 2026-05-20 | Initial URL-first TDS published from canonical chemistry registry. | initial |
This Technical Data Sheet is provided for technical reference. The Safety Data Sheet (SDS) controls in all cases where guidance differs. Values reflect Alliance Chemical canonical data at time of generation; subsequent revisions are recorded in the Revision History above.